Battery pack housing and packaging

ABSTRACT

A battery pack with a first battery and a second battery, wherein each battery is a plurality of cells connected in series, and operable in a storage mode and a use mode, a storage mode defined by isolating the first battery from the second battery, and a use mode defined by electrically connecting the first battery to the second battery. The storage mode may include: electrically isolating said first plurality of cells from said second plurality of cells or physically isolating said first plurality of cells from said second plurality of cells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/551,211, filed on Mar. 8, 2004. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to battery pack design and, morespecifically, to improved housing, packaging and transportation forbattery packs.

BACKGROUND OF THE INVENTION

International goods transportation regulations pertaining to lithium andlithium ion cells and batteries have tightened as a result of increasingconcern by regulatory officials regarding shipments of high-energydensity batteries and the proliferation of lithium ion batterytechnologies. Current regulations limit the lithium content of lithiumbatteries, and subject lithium ion batteries to a lithium equivalencycalculation where equivalent lithium content is calculated in grams on aper-cell basis to be 0.3 times the rated capacity in ampere hours. Thus,the equivalent lithium content for a battery is the rated capacity inampere hours for a single cell multiplied by 0.3 and then multiplied bythe number of cells in the battery or battery pack.

Current regulations set lithium content or equivalent content limits forcells and batteries. For a lithium metal or lithium alloy cell, thelithium content limit is not more than 1.0 gram per cell and not morethan 2.0 grams per battery. Also within the regulations is an exceptionthat allows lithium ion cells containing less than 1.5 grams ofequivalent lithium content and lithium ion batteries containing lessthan 8.0 grams of equivalent lithium content to be shipped withoutundergoing certain testing and other requirements required of largerlithium and lithium ion cells and batteries.

SUMMARY OF THE INVENTION

A battery pack according to the invention includes a housing, a firstbattery and a second battery. The first battery is disposed in thehousing and includes a first plurality of cells connected in series. Thesecond battery is disposed in the housing and includes a secondplurality of cells connected in series. The first battery and the secondbattery are operable in a storage mode and a use mode. The storage modeincludes isolating the first plurality of cells from the secondplurality of cells to meet regulatory rules. The use mode includeselectrically connecting the first plurality of cells to the secondplurality of cells and defining a voltage and a storage capacity for thebattery pack.

The battery pack may include an intermediate terminal dividing the firstplurality of cells from the second plurality of cells, or the batterypack may include a first positive terminal and a first common terminal,and a second positive terminal and second common terminal. The firstpositive terminal, first common terminal, the second positive terminaland the second common terminal terminate in a terminal block.

The battery pack may include a controller electrically connected to atleast one of the first plurality of cells and the second plurality ofcells. The controller may control one or more of the followingfunctions: charging, discharging, communication, identification, status,diagnostic, logging and switching. Further, the controller may beelectrically isolated from the second plurality of cells in the storagemode and electrically connected to the second plurality of cells in theuse mode. Also, the battery pack may include a first controller and asecond controller, wherein the first controller is electricallyconnected to the first plurality of cells and the second controller iselectrically connected to the second plurality of cells.

The battery pack housing may include a first housing part and a secondhousing part. The first plurality of cells is disposed in the firsthousing part and the second plurality of cells is disposed in the secondhousing part. The battery pack may further include a mechanicalinterface between the first housing part and the second housing part.The mechanical interface may be operable to disconnect the first housingpart from the second housing part in the storage mode and to connect thefirst housing part and the second housing part in the use mode.

The battery pack may include a separator material between the firsthousing part and the second housing part. The separator material may beoperable to separate the first housing part from the second housing partin the storage mode. The separator material may be operable to retardflame. Alternatively, the battery pack may include a separator materialoperable to separate the first plurality of cells from the secondplurality of cells, wherein the separator material is disposed in thehousing. Again, the separator material may be operable to retard flame.

The battery pack housing may include flame retardant material. Forexample, the housing may include at least one of the followingmaterials: steel, sheet metal, aluminum, magnesium or titanium. Further,the housing may include intumescent material. For example, if thehousing includes an aperture, the intumescent material may be disposedadjacent the aperture or seam. The intumescent material may be a coatingor a caulk.

A shipping method according to the invention includes shippingspecialized pallets from a factory to a distribution center, shippingspecialized pallets from a distribution center to a customer, returningspecialized pallets from the customer to the factory, and reusing thespecialized pallets. The specialized pallets separate batteries ofbattery packs during shipping to meet regulatory rules. The batteries ofthe battery packs may be separated battery housing parts. Further, thebatteries of the battery packs may be separated with separatingmaterial.

A kit box according to the invention includes a body, a first receptaclein the body and operable to receive a cordless device, a secondreceptacle adjacent the first receptacle, and a battery containerremovably placed in the second receptacle. The battery container may beconfigured to meet regulatory rules for shipping a battery pack. The kitbox may include a battery container configured to meet regulatory ruleswhen shipped with the cordless device, or the battery container may beconfigured to meet regulatory rules when shipped separately from thecordless device.

A battery pack according to the invention may include a housing and aplurality of cells disposed in the housing and electrically coupled toprovide a storage capacity between about 2.17 and 2.67 ampere-hours, toa maximum of 5.56 ampere-hours, with an equivalent lithium contentbetween about 6.5 and 8.0, to as much as 16.7. The plurality of cellsmay be 10 cells providing 36 volts, wherein the storage capacity may bebetween about 78 and 96 watt-hours, and perhaps as much as 200watt-hours.

Another battery pack according to the invention may include a housingand a plurality of two-cell units disposed in the housing andelectrically coupled to provide a storage capacity between about 2.17and 2.67 ampere-hours, to a maximum of 5.56 ampere-hours, with anequivalent lithium content between about 6.5 and 8.0, to as much as16.7. Each cell of the two-cell unit may have a storage capacity ofabout 1.08 to 1.33 ampere-hours, to a maximum of 2.78 ampere-hours. Theplurality of cells may be 20 cells or ten two-cell units, wherein eachcell of the unit is wired in parallel to the other cell and the tenunits are wired in series to form a battery pack providing 36 volts. Thestorage capacity of the battery pack may be between about 78 and 96watt-hours, and perhaps as much as 200 watt-hours.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIGS. 1-6 are schematic views of various battery packs according to theinvention;

FIG. 7 is a side view of a battery pack according to the invention;

FIG. 8 is an end view of a battery pack according to the invention;

FIG. 9 is a side view of a battery pack according to the invention;

FIG. 10 is a plan view of a battery pack according to the invention;

FIG. 11 is a diagram illustrating a method according to the invention;and

FIGS. 12 and 13 are schematic views illustrating another methodaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

Referring to the drawings, and to FIGS. 1-6 in particular, a batterypack 10 is shown in several variations (battery pack 10A-10F) andgenerally includes multiple batteries 12 having terminals for connectingto a charging device and/or cordless device. As shown, each battery pack10 includes two batteries 12, but additional batteries 12 may beincluded. Battery packs 10A, 10B and 10F are unitary in construction,while battery packs 10C, 10D and 10E are physically separable intomultiple parts.

Battery packs 10 may be configured including any number of cells toprovide the required storage capacity. For packaging and transportation,however, a range of configurations designed to both meet regulations andadequately supply capacity may be constructed. For example, a 36-volt10-cell lithium ion battery pack provides adequate capacity betweenabout 2.17 and 2.67 ampere hours, and provides preferred capacitybetween about 2.17 and 5.56 ampere hours. For a 36-volt, 20-cell lithiumbattery pack configuration, adequate capacity can be achieved with tentwo-cell units, wherein each cell provides between about 1.08 and 1.33ampere hours, and provides preferred capacity between about 1.08 and2.78 ampere hours. Each cell of the two-cell unit is wired in parallelto the other cell and the ten units are wired in series to form the pack(a 2p10s pack configuration). Each two-cell unit may provide a storagecapacity between about 2.17 and 2.67 ampere-hours, and preferablybetween 2.17 and 5.56 ampere-hours. For both the 10- and 20-cellconfigurations, the range for adequate capacity yields an equivalentlithium content between about 6.5 and 8.0, and watt hours between about18 and 96; the range for preferred capacity yields an equivalent lithiumcontent between about 6.5 and 16.7, and watt hours between about 78 and200.

Each battery 12 represents a plurality of battery cells (cell stack)connected in series to define the voltage and in parallel to define thestorage capacity for battery 12. The configuration of battery pack 10permits operational flexibility by allowing terminals in a cordlessdevice and/or charging device to selectively short one or more terminalsof batteries 12 to connect the batteries in series or parallel asdictated by charging requirements or cordless-device type. Seriesmanipulations adjust the voltage of battery pack 10 and parallelmanipulations adjust the storage capacity of battery pack 10. Forexample, two 18-volt batteries 12 connected in parallel may supply 18volts to a cordless device at a higher capacity than two 18-voltbatteries 12 connected in series. That is, the same two 18-voltbatteries 12 connected in series may supply 36 volts, but only half thecapacity of the parallel configuration.

As shown in FIG. 1, battery pack 10A includes a first battery contact20, a second battery contact 22, and a third battery contact 24 in aterminal block 26. Battery contact 20 is the B+ (positive) terminal forbattery pack 10A. Battery contact 22 is the B− (negative/common)terminal for battery pack 10A. Battery contact 24 is an intermediateterminal dividing the battery pack 10A into a pair of batteries 12, eachincluding a separate stack of cells. Battery contact 24 allows seriesmanipulations of batteries 12. Additional contacts can be provided tofurther divide the battery pack 10A into multiple batteries 12.

With reference to FIG. 2, battery pack 10B includes a pair of batteries12, each including a plurality of battery cells connected in seriesand/or parallel. The battery pack 10B includes a terminal block 38having four battery contacts: first battery contact 30, second batterycontact 32, third battery contact 34, and fourth battery contact 36.First and third battery contacts 30 and 34 are B+ (positive) terminalsfor the respective battery 12. Second and fourth battery contacts 32 and36 are B− (negative/common) terminals for the respective battery 12. Asshown, a pair of batteries 12 define the battery pack 10B, eachrepresenting a separate stack of cells connected in series and/orparallel to define the voltage and capacity of battery 12. It should benoted, however, that more than two separate cell stacks, each defining abattery 12, can be provided in the same battery pack 10B. Further,through terminal block 38, batteries 12 may be connected in series orparallel to manipulate the voltage and capacity of battery 12 or batterypack 10.

Referring now to FIG. 3, battery pack 10C includes a housing 14 havinghousing parts 16 and 18 coupled by a mechanical interface 52. Themechanical interface 52 may be any structure for joining separate parts.Further, battery pack 10C includes a controller 50 electrically coupledto a terminal block 48 having a first contact 40, a second contact 42, athird contact 44, and a fourth contact 46. The first and third batterycontacts 40, 44 are B+ (positive) terminals for respective batteries 12,while second and fourth battery contacts 42, 46 are B− (negative/common)terminals. Batteries 12 may be connected in series or parallel tomanipulate the voltage and capacity of battery 12 or battery pack 10.The controller 50 may be a microprocessor or other circuit to controlcharging and discharging of the battery pack 10, and also providessafety and control functions including communication, identification,status, diagnostic, logging and switching. The controller 50 providesthese functions for the plurality of batteries 12 included in batterypack 10, wherein batteries 12 may each including a plurality of batterycells connected in series and/or parallel.

Battery pack 10D of FIG. 4 is similar to battery pack 10C of FIG. 3 butincludes separate controllers 50 in each housing part 16, 18. In thismanner, each battery 12, which may include a plurality of battery cellsconnected in series and/or parallel, includes its own controller 50providing the various functions discussed above.

Battery pack 10E of FIG. 5 is similar to battery packs 10C and 10D ofFIGS. 3 and 4, respectively, but further includes a separator material60 to physically separate the housing parts 16, 18 for storage, displayand/or shipping. Separator material 60 functions to prevent electricalconnection between the circuits of separate batteries 12 disposed ineach of housing parts 16, 18. Further, separator material 60 preventsthe spread of flame should either housing part combust while beingstored, displayed or shipped. Thus, separator material 60 may befabricated from a material having insulative and/or flame retardantproperties.

Battery pack 10F of FIG. 6 is similar to battery pack 10B of FIG. 2, butincludes separator material 60 in battery pack 10F, which is unitary inconstruction, in order to provide the control and safety features duringstorage, display or shipping. Separator material 60 is integrated intohousing 14 of battery pack 10F to provide insulative and/or flameretardant properties between batteries 12 and within housing 14.

Battery pack housing 14, whether unitary in structure (FIGS. 1, 2 and 6)or including physically separable housing parts 16, 18 (FIGS. 3, 4 and5) may be fabricated from a non-flammable material to contain combustionwithin housing 14 or a housing part 16, 18. Further, by providing a moredurable housing, potential for damage to the batteries 12 can belessened, thereby reducing potential combustion issues. Battery packhousing 14 may be fabricated from steel, sheet metal, aluminum,magnesium or titanium, or any other material that functions to retardflame or prevent combustion. Further, battery pack housing 14 mayincorporate intumescent material. For example, plastic resin pellets maybe combined with intumescent material pellets and injection molded toform a battery pack housing 14 that retards flame or preventscombustion.

Battery packs 10 are often used with cordless products, from housewaresto power tools. Whether nickel-cadmium, nickel-metal hydride, lithium,lithium ion or lithium polymer are used as the storage medium, batterypack 10 generally includes cell stacks disposed within housing 14 andterminal block 26, 38, 48 providing electrical communication between thebattery pack 10 and the cordless product for which it is supplyingelectricity. Terminal block 26, 38, 48 and cell stacks are electricallyconnected and such electrical connections are not shown for the sake ofclarity.

With reference to FIGS. 7-10, housing 14 of battery pack 10 includes atower 70, which may include an aperture (not shown) exposing terminalblock 26, 38, 48 for electrical connection to a cordless product. Thehousing generally includes air vents 72 and may include one or morehousing parts 16, 18 or covers 78 requiring a joint 74 and/or bosses 76.To the extent apertures or seams are included in housing 14 because ofsuch joints and/or bosses, flame may escape housing 14 should combustionoccur. Thus, even where housing 14 is constructed from an insulative orflame retardant material as discussed above, the apertures and/or seamsprovide a passage for combustion to spread to other battery packs 10 orhousing parts 16, 18 during storage, display or shipping. The seamsand/or apertures may include intumescent material 80, such as caulk,disposed adjacent air vent 72, along joint 74 or about bosses 76 to plugthe aperture and/or seal the seam upon exposure to high heat or flame.Thus, upon high heat, combustion or fire in battery pack 10, intumescentmaterial 80 expands to plug or seal air vents 72, joints 74, or bosses76 to prevent the spread of combustion to other battery packs 10 orhousing parts 16, 18.

Intumescent material 80, such as a coating, may be applied to housing 14to ensure structural performance and contain any combustible materialswithin battery pack 10 or housing parts 16, 18. Similarly, intumescentmaterial 80 may be used to fabricate or coat spacers, insulation plates,gaskets, cell insulators and/or cushions within the battery pack tofurther contain combustion. Most components of the battery pack 10 maybe constructed or coated with intumescent material 80.

When shipping battery packs 10, whether a unitary construction orincluding housing parts 16, 18, specialized pallets may be used toprovide additional safeguards. As shown in FIG. 11, such pallets areshipped from a factory 100 to a distribution center 102 and then to acustomer 104, such as a retail outlet. Because of the specialized designof the pallets, it is advantageous for cost and logistical reasons toreturn the empty pallets from the customer 104 to the factory 100 forreuse, either directly or through the distribution center 102. Such adistribution method according to the invention provides transportationefficiency in meeting regulatory rules, such as by electricallyseparating batteries 12 of battery pack 10A, 10B or 10F, for example.The specialized pallets may provide separate shipment storage forhousing parts 16, 18 of battery pack 10C or 10D, for example. Thespecialized pallets may provide separating material 60 for isolatinghousing parts 16, 18, such as that shown for battery pack 10E.

With reference to FIG. 12, a kit box 120 is shown including receptaclesreceiving a cordless device 122 and a battery charging device 123, aswell as a receptacle 124 adapted to receive a container 126 for shippingbattery pack 10. Container 126 may be designed or fabricated to meetregulatory rules as described above, or any variation thereof. Becausethe kit box 120 is the shipping container for at least the cordlessdevice 122 and battery charging device 123, any regulatory rulescovering battery pack 10 may be met by separately packaging and/orshipping battery pack 10 in container 126, which is fabricated to meetregulatory rules, thereby limiting the expense of containing the entirekit in a container or kit box fabricated to meet regulatory rules. Ifshipped separately, at customer 104, container 126 is placed in kit box120 for display and sale, as shown in FIG. 13. Alternatively, batterypack 10 can be shipped, stored and displayed in a suitable container 126in kit box 120, as shown in FIG. 13, where container 126 is fabricatedto meet regulatory rules. Kit box 120 may be used by the customer tostore and transport cordless device 122.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A battery pack comprising: a first battery disposed in a firsthousing part and including a first plurality of cells connected inseries; a second battery disposed in said a second housing part andincluding a second plurality of cells connected in series; wherein saidfirst battery and said second battery are operable in a storage mode anda use mode, said storage mode including isolating said first pluralityof cells from said second plurality of cells, said use mode includingelectrically connecting said first plurality of cells to said secondplurality of cells and defining a voltage and a storage capacity for thebattery pack; and a mechanical interface that couples said first housingpart directly to said second housing part to form the battery pack;wherein at least a portion of said mechanical interface is formed onsaid first housing part and a remainder of said mechanical interface isformed on said second housing part, and said mechanical interfaceenables said first housing part to be physically disconnected from saidsecond housing part in said storage mode, and said first housing partand said second housing part to be physically connected in said usemode.
 2. The battery pack according to claim 1 wherein said firstplurality of cells includes a first positive terminal and a first commonterminal, said second plurality of cells includes a second positiveterminal and second common terminal.
 3. The battery pack according toclaim 2 further comprising a terminal block and wherein said firstpositive terminal, said first common terminal, said second positiveterminal and said second common terminal terminate in said terminalblock.
 4. The battery pack according to claim 1 further comprising acontroller electrically connected to at least one of said firstplurality of cells and said second plurality of cells and disposed in acorresponding one of said first housing part and said second housingpart.
 5. The battery pack according to claim 4 wherein said controllercontrols one or more of the following functions: charging, discharging,communication, identification, status, diagnostic, logging andswitching.
 6. The battery pack according to claim 5 wherein saidcontroller is electrically isolated from said second plurality of cellsin said storage mode and electrically connected to said second pluralityof cells in said use mode.
 7. The battery pack according to claim 1further comprising a first controller and a second controller eachdisposed in a corresponding one of said first housing part and saidsecond housing part, wherein said first controller is electricallyconnected to said first plurality of cells and said second controller iselectrically connected to said second plurality of cells.
 8. The batterypack according to claim 7 wherein said controller controls one or moreof the following functions: charging, discharging, communication,identification, status, diagnostic, logging and switching.
 9. Thebattery pack according to claim 7 wherein said first controller iselectrically isolated from said second controller in said storage modeand electrically connected to said controller in said use mode.
 10. Thebattery pack according to claim 1 further comprising a separatormaterial between said first housing part and said second housing part.11. The battery pack according to claim 10 wherein said separatormaterial is operable to separate said first housing part from saidsecond housing part in said storage mode.
 12. The battery pack accordingto claim 10 wherein said separator material is operable to retard flame.13. The battery pack according to claim 1 wherein said first housingpart and second housing part includes flame retardant material.
 14. Thebattery pack according to claim 13 wherein at least one of said firsthousing part or said second housing part includes at least one of thefollowing materials: steel, sheet metal, aluminum, magnesium ortitanium.
 15. The battery pack according to claim 1 wherein at least oneof said first housing part or said second housing part includesintumescent material.
 16. The battery pack according to claim 15 whereinat least one of said first housing part or said second housing partincludes an aperture and said intumescent material is disposed adjacentsaid aperture.
 17. The battery pack according to claim 15 wherein saidintumescent material is a coating.
 18. The battery pack according toclaim 15 wherein said intumescent material is a caulk.
 19. The batterypack according to claim 1, wherein said first housing part and saidsecond housing part are separate discrete parts.